Virtual-reality systems have wide applications in various fields, including engineering design, medical surgery practice, military simulated practice, and video gaming. Display screens used in virtual-reality systems are normally driven at low persistence, where screen persistence is the percentage of a video frame duration during which pixels of the display screen are actually lit. Low persistence, such as 10% to 20%, is typically used for moderate (e.g., 75-120 Hz) screen refresh rates to avoid image blurring during head rotations.
However, a side effect of using screens at low persistence is strobing, where multiple copies of a visual object are perceived simultaneously. Strobing is most noticeable during fast eye movements, known as saccades. During a saccade, when images are displayed using low persistence, copies of objects corresponding to different video frames are “imprinted” on the retina. In the case of a periodic structure that is made of such objects, such as a linear grid, strobing can result in visual instability where the brain fails to correctly match objects to themselves between successive video frames. The resulting sense of disorientation and illusory motion is often discomforting. Using display screens at higher persistence would require significantly faster refresh rates to avoid image blurring. With many display technologies, however, such high frequency refresh rates are not feasible.